UC3854BNG4产品信息特性Controls Boost PWM to Near-Unity Power FactorLimits Line Current Distortion To <3%World-Wide Operation Without SwitchesAccurate Power LimitingFixed-Frequency Average Current-Mode ControlHigh Bandwidth (5 MHz), Low-Offset Current AmplifierIntegrated Current- and Voltage-Amplifier Output ClampsMultiplier Improvements: Linearity, 500 mV VAC Offset (Eliminates External Resistor), 0 V to 5 V Multout Common-Mode RangeVREF GOOD ComparatorFaster and Improved Accuracy ENABLE ComparatorUVLO Options (16 V/10 V or 10.5 V/10 V)300-µA Start-Up Supply Current  说明The UC3854A/B products are pin compatibleenhanced versions of the UC3854. Like the UC3854, these products provide all of the functions necessary for active power factor corrected preregulators. The controller achieves near unity power factor by shaping the ac input line current waveform to correspond to the ac input line voltage. To do this the UC3854A/B uses average current mode control. Average current mode control maintains stable, low distortion sinusoidal line current without the need for slope compensation, unlike peak current mode control.A 1%, 7.5-V reference, fixed frequency oscillator, PWM, voltage amplifierwith soft-start, line voltage feedforward (VRMS squarer), input supply voltage clamp, and over current comparator round out the lilst of feataures. 陈伟雄 (销售部经理)电　　话：86 755 83643855移动电话：13590164498传　　真：86 755 83643855地　　址：中国广东 深圳市福田区 华强电子世界三号楼二楼2A207邮　　编：518000公司主页：http://www.htd-ic.com/